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Also Known As: Pyridoxal, Pyridoxamine, Pyridoxine hydrochloride,
Pyridoxal-5-phosphate
Vitamin B6, also called pyridoxine, is one of eight water-soluble B vitamins.
The B vitamins help the body to convert carbohydrates into glucose (sugar),
which is "burned" to produce energy. These vitamins, often referred to as the B
complex, are also essential in the metabolism of fats and protein. B complex
vitamins also play an important role in maintaining muscle tone in the
gastrointestinal tract and promoting the health of the nervous system, skin,
hair, eyes, mouth, and liver.
Vitamins B12, B6, and
B9 (folic acid) work closely together to control blood
levels of the amino acid homocysteine. Elevated levels of this substance appear
to be linked to heart disease. Plus, vitamin B6 is essential for normal brain
development and function, participating in the process of making important brain
chemicals called neurotransmitters.
Pyridoxine is an especially important vitamin for maintaining healthy nerve
and muscle cells and it aids in the production of DNA and RNA, the body's
genetic material. It is necessary for proper absorption of vitamin B12 and for
the production of red blood cells and cells of the immune system. Pyridoxine has
also been called the "woman's vitamin" because it may help relieve symptoms of
premenstrual syndrome (PMS).
In addition to other B complex vitamins, pyridoxine is considered an
"anti-stress vitamin" because it is believed to enhance the activity of the
immune system and improve the body's ability to withstand stressful conditions.
Symptoms of pyridoxine deficiency include muscle weakness, nervousness,
irritability, depression, difficulty concentrating, and short-term memory loss.
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Heart Disease
Low dietary intake of vitamin B6 is associated with higher risk of having heart
disease. This may be related to the fact that vitamin B6, together with vitamin
B9 (folic acid) and vitamin B12, help to keep homocysteine levels under control.
Homocysteine is an amino acid. Elevated levels of this amino acid are associated
with increased risk of heart disease and increased risk of stroke.
The American Heart Association recommends, for most people, that enough of
these important B vitamins be obtained from the diet, rather than taking extra
supplements. Under certain circumstances, however, supplements may be necessary.
Such circumstances include elevated homocysteine levels with known heart disease
or strong family history of heart disease at a young age.
Nausea and Vomiting during pregnancy
A recent review of scientific studies concluded that vitamin B6 may help reduce
the severity of nausea during early pregnancy.
Osteoporosis
Keeping bones healthy throughout life depends on getting sufficient amounts of
specific vitamins and minerals, including phosphorous, magnesium, boron,
manganese, copper, zinc, folate, and vitamins C, K, B6, and B12.
Vitamin B6 for Eating Disorders
Levels of important nutrients are often quite low in those with
anorexia or
bulimia. At least 20% of people with anorexia admitted to a hospital for
treatment are deficient in vitamins B2 and B6 (pyridoxine). Some research
information suggests that as many as 33% of those with an eating disorder could
be deficient in vitamins B2 and B6. Dietary changes alone, without additional
supplements, can often bring vitamin B levels back to normal. However, extra B2
and B6 may be required (which will be determined by your doctor or
nutritionist). Plus, B-complex vitamins may help alleviate stress and reduce
symptoms of depression, frequently associated with
eating disorders.
Burns
It is especially important for people who have sustained serious burns to obtain
adequate amounts of nutrients in their daily diet. When skin is burned, a
substantial percentage of micronutrients may be lost. This increases the risk
for infection, slows the healing process, prolongs the hospital stay, and even
increases the risk of death. Although it is unclear which micronutrients are
most beneficial for people with burns, many studies suggest that a multivitamin
including the B complex vitamins may aid in the recovery process. Vitamin B6,
along with other members of the B complex, may be of particular importance,
given their value in building protein. Protein is necessary to recover from any
kind of an injury. In addition, as stated earlier, the amount of B complex
needed may increase during times of stress.
Vitamin B6 for depression
Studies suggest that vitamin B9 (folate) may be associated with depression more
than any other nutrient. Between 15% and 38% of people with depression have low
folate levels in their bodies and those with very low levels tend to be the most
depressed. Many healthcare providers start by recommending a multivitamin (MVI)
that contains folate, and then monitoring the homocysteine levels in the blood
to ensure the adequacy of therapy. Elevated homocysteine levels indicate a
deficiency of folate even if the levels of folate in the blood are normal. If
the MVI alone is not enough to lower homocysteine and improve folate function,
the provider may suggest additional folate along with vitamins B6 and B12 to try
to bring the homocysteine levels down, thereby eliminating the functional folate
deficiency and, hopefully, helping to improve feelings of depression.
Premenstrual Syndrome (PMS)
A comprehensive review of studies concluded that vitamin B6 may be more
effective than placebo in improving symptoms of PMS, particularly depression.
Most studies were poorly designed, however. Still, even though the science is
not definitive, many healthcare providers and their female patients report
improvement in PMS from using vitamin B6. Therefore, how well you respond to
vitamin B6 may be very individual. Until more research is completed, talk with
your doctor about whether using B6 is appropriate and safe for you. Then, if
taking the vitamin, follow your symptoms closely. It can take up to 3 months
until any change is noticeable.
Diabetes
Preliminary evidence suggests that vitamin B6 may help control blood sugar in
people with diabetes. In a study of people with diabetes, those who received
pyridoxine alpha-ketoglutarate (a form of vitamin B6) for one month experienced
significant reductions in fasting blood sugar levels compared to those who did
not receive the supplement. More research in this area is needed before
conclusions can be drawn about the relationship between vitamin B6 and diabetes.
Human Immunodeficiency Virus (HIV)
Vitamin B6, particularly together with a complete B complex, may help alleviate
the stress associated with having HIV or AIDS.
Vitamin B6 for ADHD (Attention Deficit/Hyperactive Disorder)
Adequate levels of vitamin B6 are required for normal brain development and are
essential for the synthesis of essential brain chemicals including serotonin,
dopamine and norepinephrine. A preliminary study found that pyridoxine was
slightly more effective than methylphenidate (a medication used to treat attention deficit/hyperactivity disorder (ADHD))
in improving behavior among hyperactive children. Although intriguing, the
results of this study were not significant and no other studies have been able
to confirm these findings. Therefore, supplementation with vitamin B6 is not
considered standard treatment for attention deficit/hyperactivity disorder (ADHD).
Rheumatoid Arthritis
Low levels of vitamin B6 have been associated with rheumatoid arthritis. This
may be due to low dietary intake of vitamin B6 and other important nutrients by
people with this joint disorder. Eating a balanced diet, including a complete
vitamin B complex, is a good idea for anyone with a chronic illness, such as
rheumatoid arthritis. It is not known if taking extra vitamin B6 is of any use
if you have arthritis.
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Good dietary sources of vitamin B6 include chicken, turkey, tuna, salmon,
shrimp, beef liver, lentils, soybeans, nuts, avocados, bananas, carrots, brown
rice, bran, sunflower seeds, wheat germ, and whole-grain flour.
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Vitamin B6 can be found in multivitamins (including children's chewable and
liquid drops), B complex vitamins, or can be sold individually. It is available
in a variety of forms including tablets, softgels, and lozenges. Vitamin B6 is
also sold under the names pyridoxal, pyridoxamine, pyridoxine hydrochloride, and
pyridoxal-5-phosphate.
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People who eat a balanced diet containing good sources of vitamin B6 should
be able to meet the daily requirement without taking a supplement. Vitamin
supplements should always be taken with water, preferably after a meal. As with
all medications and supplements, check with a healthcare provider before giving
vitamin B6 supplements to a child.
Daily recommendations for dietary vitamin B6 are listed below.
Pediatric
- Newborns to 6 months: 0.1 mg (adequate intake)
- Infants 7 months to 1 year: 0.3 mg (adequate intake)
- Children 1 to 3 years: 0.5 mg (RDA)
- Children 4 to 8 years: 0.6 mg (RDA)
- Children 9 to 13 years: 1 mg (RDA)
- Males 14 to 18 years: 1.3 mg (RDA)
- Females 14 to 18 years: 1.2 mg (RDA)
Adult
- 19 to 50 years: 1.3 mg (RDA)
- Males 51 years and older: 1.7 mg (RDA)
- Females 51 years and older: 1.5 mg (RDA)
- Pregnant females: 1.9 mg (RDA)
- Breastfeeding females: 2.0 mg (RDA)
Prevention of heart disease and lowering of homocysteine levels: 3.0 mg per
day.
Nausea and vomiting during early pregnancy: studies on this topic have used
10 mg per day. The amount to use, however, should be determined together with
your obstetrician.
Therapeutic doses for some of the conditions discussed in the Uses section
have ranged from 100 to as high as 1,800 milligrams per day. Using doses higher
than 200 mg per day for long periods of time, however, may cause neurologic
disorders (see Precautions).
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Because of the potential for side effects and interactions with medications,
dietary supplements should be taken only under the supervision of a
knowledgeable healthcare provider.
Vitamin B6 can cause neurological disorders, such as loss of sensation in
legs and imbalance, when taken in high doses (200 mg or more per day) over a
long period of time. Discontinuing high doses usually leads to a complete
recovery within 6 months.
There have been extremely rare reports of allergic skin reactions to high
doses of vitamin B6 supplements.
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If you are currently being treated with any of the following medications, you
should not use vitamin B6 supplements without first talking to your healthcare
provider.
Antibiotics, Tetracycline
Vitamin B6 should not be taken at the same time as the antibiotic tetracycline
because it interferes with the absorption and effectiveness of this medication.
Vitamin B6 either alone or in combination with other B vitamins should be taken
at different times from tetracycline. (All vitamin B complex supplements act in
this way and should therefore be taken at different times from tetracycline.)
Antidepressant medications, Tricyclic
Taking vitamin B6 supplements may improve the effectiveness of certain tricyclic
antidepressants such as nortriptyline, especially in elderly individuals. Other
tricyclic antidepressants include desipramine and imipramine.
On the other hand, another class of antidepressants called monoamine oxidase
inhibitors (MAOIs) may reduce blood levels of vitamin B6. Examples of MAOIs
include phenelzine and tranylcypromine.
Vitamin B6 and Antipsychotic Medications
Preliminary evidence suggest that pyridoxine may prove useful in treating
tardive dyskinesia, a common but frustrating side effect from medications used
to treat schizophrenia. Tardive dyskinesia is marked by involuntary movements of
the mouth and tongue. More research is needed to know if vitamin B6 can help
prevent or treat this side effect.
Tuberculosis Medications
Anti-tuberculosis medications such as isoniazid (INH) and cycloserine (used for
resistant forms of tuberculosis) reduce the levels of vitamin B6 in the blood.
Birth control medications
Birth control medications may reduce blood levels of vitamin B6.
Chemotherapy
Vitamin B6 may reduce certain side effects of 5-fluorouracil and doxorubicin,
two agents used to treat cancer without reducing the effectiveness of the
chemotherapy.
Erythropoietin
Erythropoietin therapy used for severe anemia may decrease vitamin B6 levels in
red blood cells. Therefore, vitamin B6 supplementation may be necessary during
erythropoietin therapy.
Hydralazine
Vitamin B6 decreases the effectiveness of hydralazine, a medication used to
treat high blood pressure.
Levodopa
Vitamin B6 reduces the effectiveness of levodopa, a medication used to treat
Parkinson's disease.
Methotrexate
People with rheumatoid arthritis taking this medication often have low levels of
vitamin B6.
Penicillamine
Penicillamine, a medication used in the treatment of rheumatoid arthritis and
Wilson's disease (excessive amounts of copper in the body that can lead to liver
damage) may decrease levels of vitamin B6 in the body.
Vitamin B6 and Phenytoin
Vitamin B6 reduces the effectiveness of phenytoin, a medication used to treat
seizures.
Theophylline
Long-term treatment with theophylline for asthma may reduce blood levels of
vitamin B6.
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list of all supplements, vitamins
Reviewed: 01/2006
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